1. Field of the Invention
The present invention relates generally to solenoids, and, more specifically, to an electric solenoid capable of providing a supervisory warning signal in the event that the solenoid is removed from its service location.
2. Description of the Related Art
Modern commercial and industrial buildings rely on water sprinkler systems for the first fire suppression response in the event of a building fire. Areas of buildings that contain sensitive equipment or documents that would be damaged by water are commonly provided with a “preaction” or “dry” sprinkler system to minimize the risk of accidental release of water. Preaction fire suppression sprinkler systems commonly utilize electric solenoids to automatically open valves and pressurized water lines so as to supply water to sprinkler heads at the location of a detected fire. Typically a localized building fire is first detected by a heat or a smoke detector installed in the building. The activated heat or smoke detector provides a fire signal to the preaction sprinkler control system. The control system in turn energizes one or more electric solenoids installed on associated valves in the fire suppression water lines, providing pressurized water to the sprinkler heads in the vicinity of the fire. These solenoids are commonly used in a wide variety of fire suppression systems, such as, but not limited to, preaction systems, carbon dioxide systems, clean agent systems, water mist systems, etc. These systems are commonly used in commercial, industrial, and marine applications.
The National Fire Protection Association (N.F.P.A.) mandates that fire suppression systems and their component parts be regularly tested. During the testing process, the solenoids are commonly removed for their inspection, testing, and replacement if necessary. The control valves on which the solenoids are installed are normally closed, and open only when the solenoid is energized by a fire signal. Therefore, during routine inspections, the solenoids must be removed from the valves to prevent a discharge of the water or other fire suppression product during testing.
After testing, if all the solenoids are not properly replaced on their valves and functional, the integrity of the fire suppression system is compromised. Typically, no indication or warning signal is provided to the fire suppression control panel when a solenoid has been removed, or has not been properly replaced after its removal. The N.F.P.A. requires that all fire protection circuits and equipment be continuously monitored and supervised at all times for their integrity.
A need therefore exists for an apparatus for providing such a supervisory or warning signal when any solenoid in the system is removed. Preferably, such an apparatus will automatically monitor whether each individual solenoid is properly installed and ready for operation, and will provide an indication to the fire protection control panel of which particular solenoid is not properly installed, so that corrective action can be taken quickly and efficiently.